The invention relates to a static switch comprising a semi-conductor, designed to be connected in series with a load to the terminals of a DC voltage supply, and means for controlling an operating voltage of the semi-conductor comprising means for measuring the current flowing in the semi-conductor and means for regulating the operating voltage of the semi-conductor in terms of said current.
The document FR-A-2,618,176 mentions in its introduction a switch of this type comprising means designed to make the switch open when the current flowing through the latter exceeds a preset value for a certain time (circuit breaker function) and limiting, by current regulation, the current in the semi-conductor to a high value, lower than the current limits of the semi-conductor, during the time delay period. To prevent spurious trips, notably when the switch closes on a capacitive load, the time delay must be sufficiently long. However, in the event of a fault, the power dissipated in the semi-conductor is high during the time delay, which makes limitation of this time advisable. To reconcile these opposing constraints and enable progressive switching limiting the overvoltages or overcurrents, the above-mentioned document proposes a switching device, designed notably for aeronautics, comprising semi-conductors associated with resistors and connected in parallel so as to form an electronic rheostat and which are turned on successively, according to the current flowing through the device.